Compound bows are well-known and typically have a pair of primary cams with each primary cam disposed at the free end of one of a pair of limbs and around which a bowstring is wrapped under tension. A pair of harness strings may also be interconnected between the free ends of the limbs with one end of each harness string connected to a post extending from a primary cam adjacent one limb and the other end connected to the free end of the other limb. The harness strings are received in tracks formed in cam modules attached to the primary cams when the bowstring is drawn back such as to shoot an arrow. The primary cams and cam modules are contoured such that upon drawing back the bowstring energy is efficiently stored in the deflected or flexed bows limbs. The cams may also be designed to provide a "let off" which reduces the force required to further draw or hold the bow string after a certain draw length has been achieved.
In prior compound bow constructions, the harness strings and the bow string were attached to posts extending from the primary cams which created increased stresses on the primary cams and reduced the efficiency of the bows in use. Further, there were several sources of friction or interference which caused increased wear of the bowstring and harness strings of prior compound bows, such as at the ends of the tracks formed in the primary cams and cam modules and within the tracks themselves. Still further, the tracks formed in the cam modules of these bows are sized to closely receive a portion of a harness string therein. During drawing of the bowstring to load the bow, the harness strings become increasingly engaged with the tracks of the cam modules and, because of the relatively close fit between the harness string and the track increased friction was generated which reduced efficiency of the bow, and caused increased wear on the harness string and an unsteady or "jerky" draw noticeable by the user.
Further, in many compound bow constructions, the optimum draw length for maximum performance and efficiency of the compound bow in use could be exceeded thereby resulting in increased friction, a reduction in the efficiency of the bow, a loss in accuracy of an arrow shot from the bow as well as inconsistent performance of the bow over various draw lengths. To counteract this problem, aftermarket stops could be installed on the cams to engage a harness string or other portion of the compound bow at the desired maximum draw length and thereby prevent a further draw of the bowstring. However, the aftermarket stops must be precisely located on the cam modules to ensure optimum performance of the bow and may cause increased vibration of the bow in use and thereby increase the wear on the bow and its accessories.
Additionally, some prior bows have a cam module attached to a primary cam by only two screws. This is insufficient to accurately locate and fly hold the cams to prevent slight relative movement between them. Thus, some prior bows have a cam module locator stop fixed to or integral with the primary cam to aid in locating the cam module relative to the primary cam by providing a stop surface engageable by the cam module in assembly. This locator stop must be accurately formed on the primary cam and greatly increases the cost to make the primary cam.